Many devices use a quarter-turn or bayonet-style attachment in applications where quick installation and removal are desired. For example, lead-acid batteries use this method of attachment for securing the vent caps within the vent ports. The same attachment method is often used in the manufacture of battery watering systems to mount the watering valves to the vent ports.
A typical prior art battery cover assembly for a battery includes a battery vent cap and a battery cover having a vent port. The vent cap and the vent port each include a pair of diametrically opposed bayonet tabs. The tabs have substantially similar lead angles. The individual vent cap is manually tightened within the vent port as the vent cap is rotated 90 degrees clockwise (quarter-turn method) by field personnel. This tightening secures the vent cap and provides a seal between a flange of the vent cap and a rim of the vent port. The seal prevents a migration of battery acid out of the battery. The vent cap can be easily rotated 90° counterclockwise by the user to remove the vent cap from the vent port for routine battery maintenance and inspections. The described bayonet attachment system has been used for decades and continues to be a common system of attachment for battery vent caps and watering systems on deep-cycle batteries.
Recently, a push-in style of cap has been introduced, particularly for caps which are part of battery watering systems. The push-in style of construction enables the cap to be pushed into place without substantial rotation. Accordingly, an installation of the cap is relatively easy compared to the prior quarter-turn method of installation. The push-in caps are being used on an assembly line by battery manufacturers and manufacturers of battery-powered equipment such as golf cart manufacturers, for example. The caps also enable faster installation of battery watering systems. After the caps are pushed into place, the caps can rotate 360 degrees within the vent port, which is helpful in aligning connection ports on the caps with watering system tubing.
The push-in caps are tightly fitted into the vent port to improve a seal therebetween and prevent the cap from dislodging as the battery cover flexes during use. The tight fit also assists in maintaining an appropriate seal over a wide range of temperatures and vibrations experienced by the battery. The push-in caps, however, are not without problems. For example, to remove the push-in caps from the vent ports for routine battery maintenance, field personnel use screwdrivers or channel-lock wrenches to pry out or pull out the caps, potentially damaging the battery cover and/or the caps. It also can be hazardous because it involves the use of a metal tool on the battery cover, which can cause dangerous sparks that can trigger explosions. Accordingly, the benefits provided by the prior art push-in caps are offset by the difficult, potentially damaging, and hazardous removal of the caps for routine battery maintenance.
It is an object of the present invention to produce a battery vent cap which is easily installed and removed.